Introduction: There are about 5 million truck drivers in India. As the eye sight plays a prominent role in safe driving, the truck driver's visual tasks/vision sense needs to be checked periodically.Aims: The aim of the study was to detect refractive errors and color blindness among truck drivers.Materials and Methods: We carried out a cross-sectional study on truck drivers. Truck drivers were screened at their resting places after obtaining their prior consent. In our study, we screened 140 truck drivers in various age groups.Statistical analysis used: We have analyzed the data obtained from the study by using Microsoft Office Excel 2007.Results: Out of 140 truck drivers screened, the number of truck drivers with visual acuity 6/6 (normal vision) was 100 (71.43%) while the drivers with refractive errors were 40 (28.57%). Of the 40 truck drivers with refractive errors; 11 were having myopia, 20 hypermetropia, and nine were found to have astigmatism. In the entire study, 44 truck drivers were found to have presbyopia. None of the divers had color blindness and/or night blindness.Conclusions: Most of the truck drivers having defective vision were in the age group of 41-60 years. This indicates that the drivers of this age group should be screened frequently to detect visual defects and they should be encouraged to wear corrective glasses (spectacles) to have normal visual acuity.

As the vision sense of truck drivers plays a prominent role in safe driving on Indian roads, [1] their visual tasks needs to be checked. The quality of vision depends on good visual acuity, normal color vision, and absence of night blindness. [2] So far, no study has been carried out in India to evaluate their visual skills. The aim of the study was to detect refractive errors and color blindness among truck drivers. The study purpose was to create awareness among the truck drivers and transport officials regarding the importance of visual abilities in driving profession.

Materials and Methods

We carried out a cross-sectional study on truck drivers. The study was done for a period of 2 months from June to July 2011 and 140 truck drivers were screened to detect their visual function. The study was approved by Institutional Ethical Committee of our institute and the participant's confidentiality was guaranteed. With the assistance of the lorry owners' association in our city, we identified the resting places of truck drivers. After approaching truck drivers at their resting places with the necessary ophthalmic equipment, they were explained the examination procedure and their informed consent were taken. The truck drivers with a valid heavy motor vehicle license and not having any systemic diseases were included in this study.

Gross examination of eyes

The person to be tested was asked to sit in front of the examiner. Light was thrown over the eyes by using a torch and both the eyes were examined for any anomalies (such as lid deformities, pupillary reflexes, and orbital deformities). Corneal opacities, depth of the anterior chamber, and lens opacities were examined by using a slit lamp biomicroscope.

Past and personal history

Each person was asked regarding the history of any illness followed by their personal habits like smoking/chewing tobacco, alcohol consumption, etc.

Procedure for recording visual acuity

Each person was tested individually for recording their visual acuity. The person to be examined was asked to sit at a distance of 6 m (20′) from Snellen's test chart. A metallic trial frame was placed in front of the eyes and the person was asked to read the test types by closing the opposite eye with an occluder. If the person is illiterate he was asked to show the directions of E-test types. The vision was recorded as per the standard procedure:- 6/60, 6/36, 6/24, 6/18, 6/12, 6/9, 6/6. Those who could not identify the test types were asked to count the fingers of the examiner from a distance of 5, 4, 3, 2, 1, 0.5 m, and close to the face. The persons who might not count the fingers were asked to tell the movements of hand of the examiner placed in front of their eyes. If the person still could not tell the movements of hand then he was asked to tell the direction of falling of the light of a torch. [3] The refractive errors were determined using autorefractometer.

Recording of color vision deficiency

The person to be tested for recording color vision [4] was asked to sit in front of the examiner. He was shown, the standard Ishihara's color plates at a reading distance of about 30 cm. The person was screened first for red-green color deficiency by showing the appropriate color plates, and then for blue-green color deficiency by showing the related color plates. The person was enquired about night blindness as per standard protocol. [5]

Results

Out of 140 truck drivers screened under this study, 40 (28.57%) were having refractive errors [Table 1]. Number of truck drivers with visual acuity of <6/18 (6/18 is considered to be useful vision) was 21 (15%). The occurrence of color blindness and night blindness were not detected in any one of the truck drivers. Of the 40 truck drivers with refractive errors, 11 (27.5%) were identified to have myopia (short sightedness), 20 (50%) were having hypermetropia (far sightedness), and nine (22.5%) were having astigmatism. Irrespective of refractive errors, 44 truck drivers were having presbyopia (inability to see near objects).

In general, many studies have been conducted on truck drivers in relation to HIV/AIDS. [6],[7] However so far, no study has been conducted in India to evaluate their visual skills, which is an important aspect of their profession. The results of the study show that the prevalence of refractive errors started increasing from 41 years of age and went on increasing with the age. [8] None of the truck drivers in any age group had color blindness and/or night blindness. The percentage of truck drivers with refractive errors as obtained from our study was 28.57% [Figure 1]. On contrary to this, the percentage of truck drivers with refractive errors from similar studies carried out in Nigeria was 18.1 [9] and 19.3%. [10] Another study carried out in Turkey reported the prevalence of refractive errors in truck drivers as 21.5%. [11] This shows that the magnitude of refractive errors in truck drivers in India is much higher and it also shows the need for stringent medical check-ups to detect visual abnormalities in Indian truck drivers. Though they were driving the vehicles with subnormal visual acuity, they did not identify this as disability. Moreover, many of them were unaware of having an eye check-up with a qualified ophthalmologist. We also observed that wearing spectacles was a taboo amongsome truck drivers. After getting examined in our study, many drivers felt the need of correcting their refractive errors by wearing proper spectacles.

We are thankful to the Indian Council of Medical Research for providing Short Term Studentship (ICMR STS 2011) to Dr. B Murali Krishna. We are grateful to Siddhartha Academy of General and Technical Education, Vijayawada for providing hospital facility. We sincerely thank Dr. C Nageswara Rao, Director General; Dr. Sudha D Deshpande, Principal and Dr. K S N Rao, Medical Superintendent for their constant support and encouragement.